For the strongest built-in protection, keep Microsoft Defender real-time protection, cloud-delivered protection, tamper protection, SmartScreen reputation checks, and Microsoft Defender Firewall on. Keep exclusions narrow. Consider Controlled folder access if you can accommodate occasional app blocks. The settings are in the Windows Security app, although labels and availability can differ on managed PCs or when another antivirus provider is active.
Recommended Windows Security settings at a glance
| Setting | Recommendation | What to consider |
|---|---|---|
| Real-time protection | On | Checks files and programs as they are accessed or run. |
| Cloud-delivered protection | On | Lets Defender receive updated protection improvements while connected. |
| Tamper protection | On | Helps stop malicious apps from changing important Defender settings. |
| Automatic sample submission | On if you are comfortable sharing suspicious files with Microsoft for evaluation | Microsoft says you may be alerted if a requested file contains personal information so you can decide whether to send it. |
| Exclusions | None unless necessary; keep any exclusion specific | Excluded files and folders are not checked by Defender real-time scanning. |
| Controlled folder access | Consider enabling | Can block untrusted apps from changing protected folders; legitimate apps may need approval. |
| SmartScreen / reputation-based protection | On | Helps assess apps, files, sites, and downloads. |
| Microsoft Defender Firewall | On for each network profile | Use Private for trusted networks and Public for untrusted networks. |
These controls address different risks: file scanning, suspicious app and website reputation, unwanted changes to protected folders, and network traffic. None replaces the others. Microsoft describes the main antivirus settings in its Virus and threat protection guidance.
Turn on Defender antivirus protection
Check the main protection switches
- Open Windows Security.
- Select Virus & threat protection, then Manage settings.
- Turn on Real-time protection, Cloud-delivered protection, and Tamper protection, if available.
Real-time protection scans files and programs as you access or run them. Microsoft warns that files opened or downloaded while it is off are not scanned during that period; Windows turns the setting back on automatically after a short while. Do not treat that automatic reset as a safe way to run unscanned files.
Cloud-delivered protection provides Defender with updated improvements when the device is connected. Tamper protection helps prevent malicious apps from changing important Microsoft Defender Antivirus settings. If these options are unavailable or managed by an administrator, the device may be subject to organizational policy.
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Check which antivirus provider is active
If you install compatible third-party antivirus software, Microsoft Defender Antivirus may switch itself off automatically. In Windows Security, open Virus & threat protection and use Who’s protecting me? or Manage providers to see the active provider. Do not assume that Defender is the active antivirus just because the Windows Security app is present, and do not try to run multiple real-time antivirus engines at once.
Decide about automatic sample submission
Automatic sample submission can send suspicious files to Microsoft for evaluation. Leave it on if you are comfortable with that sharing. Microsoft says it may notify you when a requested file appears to contain personal information, allowing you to decide whether to send it. See Microsoft’s description of Virus & threat protection settings for details.
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- Biometric logins. Encrypted authentication. And, of course, advanced antivirus defenses. Everything you need, plus more, to protect you against the latest cyberthreats.
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Use exclusions sparingly and keep protection current
Make exclusions as narrow as possible
An exclusion reduces scanning for the selected file, folder, file type, or process. Avoid excluding broad folders or whole drives to work around a warning or performance issue. Microsoft notes that Defender real-time scanning will no longer check excluded items, although scheduled Defender scans or a third-party antimalware product may still scan them. Remove an exclusion when it is no longer needed.
Run scans when useful
Windows Security scans automatically. Use Quick scan for a routine check; open Scan options for a full or custom scan when you need to check more extensively or focus on particular locations. A manual scan does not replace current security intelligence or ongoing real-time protection.
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Check for security intelligence updates
- Open Windows Security and select Virus & threat protection.
- Under Virus & threat protection updates or Protection updates, select Check for updates.
You can also receive security intelligence through Windows Update. Microsoft’s Windows Security overview explains the app’s built-in protection and update role.
Consider Controlled folder access for ransomware defense
Controlled folder access can prevent unknown or untrusted apps from changing files in protected folders. Windows commonly protects Documents, Pictures, Videos, Music, and Desktop, and you can add other folders. This is a useful extra barrier, but it can interrupt normal work when a legitimate app has not been trusted yet.
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- Open Windows Security and choose Virus & threat protection.
- Select Manage ransomware protection.
- Turn on Controlled folder access, if the option is available.
- Test the apps you rely on, especially those that save or modify files in protected folders.
- If a trusted app is blocked, use the option to allow an app through Controlled folder access, and approve only apps you trust.
Microsoft explains the feature and app permissions in its ransomware protection guidance. OneDrive-based ransomware data recovery can add a recovery layer for synced files. A backup helps you restore data; it does not mean a device cannot be infected.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Keep app, browser, and network protections enabled
SmartScreen and reputation-based protection
Open Windows Security > App & browser control and review the reputation-based protection settings. Leave Microsoft Defender SmartScreen protection on for apps, files, sites, and downloads when those options are available. These checks complement antivirus scanning by assessing reputation rather than simply scanning a file after it reaches the device.
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Windows 11 also includes Smart App Control on supported configurations. Microsoft says Smart App Control is not available in Windows 10; it is an additional Windows 11 control, not a replacement for SmartScreen or antivirus. Options may differ by edition or device-management policy. See Microsoft’s App & browser control guidance.
Microsoft Defender Firewall
Keep Microsoft Defender Firewall on for the network profiles you use. The Private profile is intended for trusted networks, such as a home network you control; Public is for untrusted networks. Check the current network profile under Windows Security > Firewall & network protection. Avoid turning off the firewall as a general troubleshooting step. Microsoft’s Firewall and network protection guide describes the profiles and controls.
Windows 10 needs a separate support decision
As of October 5, 2026, standard Windows 10 support has ended. Microsoft says support ended on October 14, 2025, including ordinary software and security updates and technical assistance. Keeping antivirus and firewall settings enabled remains sensible, but it does not restore missing operating-system security fixes.
Microsoft points users to upgrading an eligible PC to Windows 11 or enrolling in consumer Extended Security Updates (ESU) if they need more time. Microsoft states that ESU can protect eligible devices through October 12, 2027; eligibility and enrollment conditions apply, so check the current Windows 10 support information before relying on ESU.
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